TITLE: GCN CIRCULAR NUMBER: 45515 SUBJECT: GRB 260903A: SAO RAS optical observations DATE: 26/09/04 15:01:32 GMT FROM: Alexander Moskvitin at SAO RAS <mosk@sao.ru> A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of the GRB 260903A discovered by the SVOM (Brunet et al., GCN 45499), also followed by EP (Li et al., GCN 45510) with the Zeiss-1000, 1-m SAO RAS telescope + new CCD photometer. A set of 16 x 300 sec images in Rc band were obtained on September 3, 19:58:07--21:32:51 (mid. time = 8.1358 hours). The OT (Li et al., GCN 45504; Saccardi et al., GCN 45505; Malesani et al., GCN 45508; Russeil et al., GCN 45509) is clearly detected in our stacked image. Details of the observation are the following. Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-09-03 19:58:07 0.33899 16*300 Rc 22.45 +/- 0.09 24.0 The preliminary photometry (Vega) is based on nearby SDSS stars (Lupton 2005 transformation) and not corrected for Galactic extinction. _____________________________________________ Alexander Sergeevich Moskvitin, Ph. D., researcher, Optical Transient Physics Laboratory (#523), SAO RAS, 369167, Nizhnij Arkhyz, Karachai-Cherkessia, Russia, +7(928)3946958, mosk@sao.ru View this GCN Circular online at https://gcn.nasa.gov/circulars/45515. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...